Due to its high mRNA abundance, protein expression in Gln-sensitive cell lines and previous studies showing extensive transcriptional and post-translational regulation of SLC38A2 under microenvironmental stress conditions,12,19 we investigated in more detail the role of SLC38A2 under glutamine starvation and endoplasmic reticulum (ER) stress in breast cancer cell lines. The gene discussed is SLC38A2; the disease is breast cancer.